US3136950A - Double sideband suppressed carrier balanced modulator using a ferrite circulator - Google Patents

Double sideband suppressed carrier balanced modulator using a ferrite circulator Download PDF

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US3136950A
US3136950A US142246A US14224661A US3136950A US 3136950 A US3136950 A US 3136950A US 142246 A US142246 A US 142246A US 14224661 A US14224661 A US 14224661A US 3136950 A US3136950 A US 3136950A
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shorting
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transmission line
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Richard C Mackey
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SPACE TECHNOLOGY LAB Inc
SPACE TECHNOLOGY LABORATORIES Inc
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/52—Modulators in which carrier or one sideband is wholly or partially suppressed
    • H03C1/54—Balanced modulators, e.g. bridge type, ring type or double balanced type
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C7/00—Modulating electromagnetic waves
    • H03C7/02—Modulating electromagnetic waves in transmission lines, waveguides, cavity resonators or radiation fields of antennas

Definitions

  • the modulator employing a ferrite circulator having a plurality of ports identified serially in the direction of propagation of energy in said circulator.
  • a microwave carrier signal is generated and directed into a first port.
  • a transmission line terminated at one end is connected at the other end to a second port.
  • the transmission' line contains a controllable shorting means preferably in the form of a crystal diode located intermediate said second port and said terminated end of said line.
  • the distance between said crystal diode and said terminated end is preferably, an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal.
  • the crystal diode is preferably modulated by a substantially symmetrical square wave or a sinusoidal waveform depending on the ultimate use being made of the disclosed modulator.
  • the utilization circuit in the form of a suitable antenna is connected to a third port and a matched load terminating device is connected to a United States Patent the modulation signal.
  • diode 14 controls the shorting or non-shorting characteristics of the diode by biasing the diode either in the reverse direction or in the forward direction.
  • the crystal diode 14 is located a distance measured substantially as a quarter-wavelength of the carrier frequency generated by the microwave signal generator 11 from the shorting plunger 12.
  • a utilization circuit 16 adapted to receive the modulated carrier output signal from the circulator 10 is connected to port C.
  • Port D is subsequently connected to a matched load circuit 17 to complete the circuit. It is well recognized that an equivalent three port circulator with a built-in matched load circulator may also be used.
  • a microwave carrier signal enters port A and leaves the circulator by port B.
  • This signal from port B travels along the line 13 and is reflected from the crystal diode 14 or the shorting plunger 12 depending on the modulation voltage applied to the crystal diode.
  • the crystal is biased in the forward direction it will experience a small insertion loss and the microwave signal from port B will pass therethrough to be eventually reflected by the shorting plunger 12 which terminated the line 13.
  • the crystal is biased in the reverse direction a large insertion loss results and the microwave signal from port B will be reflected by the reverse biased crystal diode 14.
  • the insertion loss in both cases results mainly from reflective losses with very little power being absorbed by the crystal.
  • the reflected energy from either the crystal diode 14 or the shorting plunger 12 enters port B and is circulated to port C.
  • phase of the signal at port C must change by 180 in accordance with This condition is fulfilled when the shorting plunger 12 is adjusted to be one-qurter of a guided wavelength behind the plane of the crystal thereby causing the path length from port A to port C to be changed by one-half a guided wavelength.
  • carrier suppression varies between 20 and 30 db depending upon the crystal used, but may be increased to greater than 50 db by the addition of a slide scre w tuner 18 on the line 13 located between the crystal diode 14 and port B.
  • the tuning of 1 the disclosed modulator is very straightforward compared fourth port for dissipating unutilized residual energy in said circulator. 7
  • FIG. 10 is a schematic diagram of a balanced modulator constructed in accordance with the principles of the present invention.
  • a ferrite circulator 10 having four symmetrically located ports identified as A, B, Cyand D.
  • microwave carrier signal is generated by a microwave signal generator 11 and fed into port A of circulator 10.
  • a property of circulator 10 is that energy enterlng port A is circulated in the-direction of the arrow and leaves by means of port B.
  • any signal entering por t B will be circulated around and out port C and in a similar manner energy entering port C will circulate and leave by means of port D.
  • a tunable detector mount term mates port B. This termination is accomplished by means of a shorting plunger 12 located at the end of a transmission line 13 which is connected to port B.
  • the tunable detector is preferably a crystal diode 14 located intermediate the shorting plunger 12 and the port B.
  • a two-level modulation signal generator 15 is connected to the crystal to prior art devices and less critical. With a square wave of modulation applied, from the generator 15 the shorting plunger 12 is adjusted for minimum carrier amplitude at the utilization circuit 16 and then final carrier null will be achieved with the reactive slide screw tuner 18.
  • the balanced modulator is in reality a special case of phase modulation and that there is an equivalence between phase modulation and balanced modulation.
  • phase modulation For the particular case of a rectangular modulation waveform and a phase modulation index of 1r/ 2 the equivalence will be demonstrated.
  • e(t) E[1:m (t)] cos w t
  • a modulator comprising a ferrite circulator having a plurality of ports identified serially inv the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into a first port, a transmission line terminated at one end and connected at the other end to a second port, said transmission line containing a controllable shorting means lo- .cated intermediate said second port and said terminated end of said line, said controllable shorting means being spaced a distance substantially equal toan odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line, means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to a third port for receiving said modulated carrier output signal, and means connecting said ferrite circulator for dissipating unutilized residual energy in said circulator.
  • a modulator comprising a ferrite circulator having a first, second, thirdand fourth port identified serially in the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, said controllable
  • the described device may obviing device connected to said fourth port for dissipating unutilized residual energy in-said circulator.
  • a modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a crystal diode located intermediate said second port and said terminated end of said line, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwace carrier signal from said shorted end of said transmission line, means for modulating said crystal diode from a substantially non-shorting condition 'to a shorting condition, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
  • a modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a crystal diode located intermediate said second port and said terminated end of said line, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line, means for modulating said crystal diode with a biasing current varying from a forward to a reverse direction whereby said crystal diode varies from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
  • a modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in said circulator,
  • ' means for generating a microwave signal and directing said signal into said first port a transmission line terminated at one end by a variable position shorting plunger and connected at the other end to said second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, said controllableshorting means being spaced at distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line, a tuning means located on said transmission line between said second port and said controllable shorting means, means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to said third port for receiving said modulated carn'er output signal, and a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
  • a balanced modulator comprising a ferrite circulator having a first, second, third and fourth port identified circuit connected to said third port for receiving said seriallyiin the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, modulating means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, said controllable shorting means being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line for causing the modulated carrier signal at said third port to change 180 in accordance With said modulation-means, a utilizing circuit connected to said third port for receiving said modulated carrier said microwave carrier signal from said shorted end of said transmission line for causing the modulated carrier signal
  • a bi-phase modulator comprising a ferrite circulator having a plurality of ports identified serially in the direccrystal diode located intermediate said second port and 7 said terminated end of said line, modulating means for modulating said crystal diode from a substantially nonshorting condition to a shorting condition, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-Wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line for causing the modulated carrier signal at said third port to change 180 in accordance wtih said modulation means, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and a matched terminating device connectedrto said fourth port for dissipating unutilized residual energy in said circulator.
  • a balanced modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in tion of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into a phase shift, a transmission line terminating at one end and connected at the other end to a second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, the phase modulation being determined by the distance between said controllable shortingmeans from said shorted end of said transmission line, said phase shift being determined by the following relationship: I r r Where:
  • said circulator means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end by a' variable position shorting plunger and connected at the other end to said second port, said transmission line containing a crystal diode located intermediate said second port and said ter-t minated end of said line, modulating means for modulating said crystal diode from asubstantially non-shorting condit ion to a' shorting condition, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to a third port for receiving said modulated carrier output signal, and means connecting said ferrite circulator for dissipating unutilized residual energy in said circulator.

Description

June 9, 1964 R. CI MACKEY DOUBLE SIDEBAND SUPPRESSED CARRIER BALANCED MODULATOR USING A FERRITE CIRCULATOR Filed Oct. 2, 1961 MATCHED LOAD cIRcuIT D ID MODULATED 1 cARRIER cARRIER OUTPUT /|I INPUT MICROWAVE CIRCULATOR UTILIZATION SIGNAL GENERATOR cIRcuIT ZIS :IB -SLIDE SCREW TUNER SHIFT SHORTING i PLUNGER AGENTS.
3,136,950 DOUBLE SIDEBAND SUPPRESSED a 1 l R BALANCED MODULATOR USING A FERRITE CWCULATOR Richard C. Macirey, Reseda, Califi, assignor to Space Technology Laboratories, Inc., Los Angeles, Calif., a corporation of Delaware Filed Oct. 2, 1961, Ser. No. 142,246 9 Claims. (Cl. 325-438) This invention relates primarily to modulators and more specifically to. a microwave balanced modulator in waves, rectangular periodic, or rectangular pseudo-random.
In this invention there is disclosed a preferred embodiment of the modulator employing a ferrite circulator having a plurality of ports identified serially in the direction of propagation of energy in said circulator. A microwave carrier signal is generated and directed into a first port. A transmission line terminated at one end is connected at the other end to a second port. The transmission' line contains a controllable shorting means preferably in the form of a crystal diode located intermediate said second port and said terminated end of said line.
The distance between said crystal diode and said terminated end is preferably, an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal. However, the exact distance used is a function of the degree of modulation desired since the complete system need not be operated as a balanced modulator. The crystal diode is preferably modulated by a substantially symmetrical square wave or a sinusoidal waveform depending on the ultimate use being made of the disclosed modulator. The utilization circuit in the form of a suitable antenna is connected to a third port and a matched load terminating device is connected to a United States Patent the modulation signal.
3,136,950 Patented June 9, 1964 diode 14 and controls the shorting or non-shorting characteristics of the diode by biasing the diode either in the reverse direction or in the forward direction. In the preferred mode as a balanced modulator the crystal diode 14 is located a distance measured substantially as a quarter-wavelength of the carrier frequency generated by the microwave signal generator 11 from the shorting plunger 12. A utilization circuit 16 adapted to receive the modulated carrier output signal from the circulator 10 is connected to port C. Port D is subsequently connected to a matched load circuit 17 to complete the circuit. It is well recognized that an equivalent three port circulator with a built-in matched load circulator may also be used.
In operation a microwave carrier signal enters port A and leaves the circulator by port B. This signal from port B travels along the line 13 and is reflected from the crystal diode 14 or the shorting plunger 12 depending on the modulation voltage applied to the crystal diode. For example, if the crystal is biased in the forward direction it will experience a small insertion loss and the microwave signal from port B will pass therethrough to be eventually reflected by the shorting plunger 12 which terminated the line 13. On the other hand, if the crystal is biased in the reverse direction a large insertion loss results and the microwave signal from port B will be reflected by the reverse biased crystal diode 14. The insertion loss in both cases results mainly from reflective losses with very little power being absorbed by the crystal. For operation as a balanced modulator the reflected energy from either the crystal diode 14 or the shorting plunger 12 enters port B and is circulated to port C.
For operation as a balanced modulator the phase of the signal at port C must change by 180 in accordance with This condition is fulfilled when the shorting plunger 12 is adjusted to be one-qurter of a guided wavelength behind the plane of the crystal thereby causing the path length from port A to port C to be changed by one-half a guided wavelength. For X-band operation it has been determined that carrier suppression varies between 20 and 30 db depending upon the crystal used, but may be increased to greater than 50 db by the addition of a slide scre w tuner 18 on the line 13 located between the crystal diode 14 and port B. The tuning of 1 the disclosed modulator is very straightforward compared fourth port for dissipating unutilized residual energy in said circulator. 7
Further objects and advantages of the present invention will be described as the description progresses, reference now being made to the accompanying drawing which is a schematic diagram of a balanced modulator constructed in accordance with the principles of the present invention. There is shown a ferrite circulator 10 having four symmetrically located ports identified as A, B, Cyand D. A
microwave carrier signal is generated by a microwave signal generator 11 and fed into port A of circulator 10. A property of circulator 10 is that energy enterlng port A is circulated in the-direction of the arrow and leaves by means of port B. In addition any signal entering por t B will be circulated around and out port C and in a similar manner energy entering port C will circulate and leave by means of port D. In order to use the device as a balanced modulator a tunable detector mount termmates port B. This termination is accomplished by means of a shorting plunger 12 located at the end of a transmission line 13 which is connected to port B. The tunable detector is preferably a crystal diode 14 located intermediate the shorting plunger 12 and the port B. A two-level modulation signal generator 15 is connected to the crystal to prior art devices and less critical. With a square wave of modulation applied, from the generator 15 the shorting plunger 12 is adjusted for minimum carrier amplitude at the utilization circuit 16 and then final carrier null will be achieved with the reactive slide screw tuner 18.
It can be demonstrated mathematically that the balanced modulator is in reality a special case of phase modulation and that there is an equivalence between phase modulation and balanced modulation. For the particular case of a rectangular modulation waveform and a phase modulation index of 1r/ 2 the equivalence will be demonstrated.
Consider the expression for a carrier amplitude modulated by a function of time f(t) of unit amplitude e(t) =E[1+m ;f(t) cos w where m is the modulation index and w is the carrier frequency.
For the case of a rectangular waveform of unit amplitude f(t) :1 1 (t) with the time dependence not specified; then,
e(t) =E[1:m (t)] cos w t The balanced modulator performs the operation e(t) =E[1+m (t)] cos w t-E[l m (t)] cos w t which combines to 1 [i2m (t)] cos w t I invention illustrated herein.
e(t) :E SiI1[w ti1r/2(t)] e(t) '-E(t) cos w t This equivalence is the basis of operation of a number of microwave balanced modulators. Phase modulation there fore is accomplished by applying the modulation signal to the microwave crystal diode thereby causing a variation in reflection coefficient. ously be used to provide bi-phase modulation of any degree as determinedby the positionof the shorting plunger with respect to the crystal diode. The relationship is:
where =phase shift in radians l=length between diode and shorting plunger A guided. wavelength This completes the description of the embodiment of the However, many modifications and advantages thereof will beapparent to persons skilled in the art without departing from the spirit and scope of this invention. For example, many other types of controllable shorting devices other than a crystal diode may be used. In addition it is contemplated that different types of modulating signals such as sinusoidal modulation may be used since the modulation amplitude and source impedance cause the diode to be operated essentially in a switching mode.
Accordingly, it is desired that this invention not be lim ited to the particular details of the embodiment disclosed herein, except as defined by the appended claims.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
' l. A modulator comprising a ferrite circulator having a plurality of ports identified serially inv the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into a first port, a transmission line terminated at one end and connected at the other end to a second port, said transmission line containing a controllable shorting means lo- .cated intermediate said second port and said terminated end of said line, said controllable shorting means being spaced a distance substantially equal toan odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line, means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to a third port for receiving said modulated carrier output signal, and means connecting said ferrite circulator for dissipating unutilized residual energy in said circulator.
2. A modulator comprising a ferrite circulator having a first, second, thirdand fourth port identified serially in the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, said controllable The described device may obviing device connected to said fourth port for dissipating unutilized residual energy in-said circulator.
3. A modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a crystal diode located intermediate said second port and said terminated end of said line, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwace carrier signal from said shorted end of said transmission line, means for modulating said crystal diode from a substantially non-shorting condition 'to a shorting condition, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
4. A modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a crystal diode located intermediate said second port and said terminated end of said line, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line, means for modulating said crystal diode with a biasing current varying from a forward to a reverse direction whereby said crystal diode varies from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
5. --A modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in said circulator,
' means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end by a variable position shorting plunger and connected at the other end to said second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, said controllableshorting means being spaced at distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line, a tuning means located on said transmission line between said second port and said controllable shorting means, means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to said third port for receiving said modulated carn'er output signal, and a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
6. A balanced modulator comprising a ferrite circulator having a first, second, third and fourth port identified circuit connected to said third port for receiving said seriallyiin the direction of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end and connected at the other end to said second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, modulating means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, said controllable shorting means being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line for causing the modulated carrier signal at said third port to change 180 in accordance With said modulation-means, a utilizing circuit connected to said third port for receiving said modulated carrier said microwave carrier signal from said shorted end of said transmission line for causing the modulated carrier signal at said third port to change 180 in accordance with said modulation means, a slide screw tuner located on said transmission line between said second port and said crystal diode, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and'a matched terminating device connected to said fourth port for dissipating unutilized residual energy in said circulator.
9. A bi-phase modulator comprising a ferrite circulator having a plurality of ports identified serially in the direccrystal diode located intermediate said second port and 7 said terminated end of said line, modulating means for modulating said crystal diode from a substantially nonshorting condition to a shorting condition, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-Wavelength at the operating frequency of said microwave carrier signal from said shorted end of said transmission line for causing the modulated carrier signal at said third port to change 180 in accordance wtih said modulation means, a utilizing circuit connected to said third port for receiving said modulated carrier output signal, and a matched terminating device connectedrto said fourth port for dissipating unutilized residual energy in said circulator.
8. A balanced modulator comprising a ferrite circulator having a first, second, third and fourth port identified serially in the direction of propagation of energy in tion of propagation of energy in said circulator, means for generating a microwave signal and directing said signal into a phase shift, a transmission line terminating at one end and connected at the other end to a second port, said transmission line containing a controllable shorting means located intermediate said second port and said terminated end of said line, the phase modulation being determined by the distance between said controllable shortingmeans from said shorted end of said transmission line, said phase shift being determined by the following relationship: I r r Where:
=phase shift in radians l=length between said controllable shorting means and said shorted end of said transmission line A =gnided wavelength,
said circulator, means for generating a microwave signal and directing said signal into said first port, a transmission line terminated at one end by a' variable position shorting plunger and connected at the other end to said second port, said transmission line containing a crystal diode located intermediate said second port and said ter-t minated end of said line, modulating means for modulating said crystal diode from asubstantially non-shorting condit ion to a' shorting condition, said crystal diode being spaced a distance substantially equal to an odd multiple of a quarter-wavelength at the operating frequency of means for modulating said controllable shorting means from a substantially non-shorting condition to a shorting condition, a utilizing circuit connected to a third port for receiving said modulated carrier output signal, and means connecting said ferrite circulator for dissipating unutilized residual energy in said circulator.
r References Cited in the file of this patent UNITED STATES PATENTS 2,981,837 Ruthrofl? Apr. 25, 1961 Ruthroff Aug. 1, 1961

Claims (1)

1. A MODULATOR COMPRISING A FERRITE CIRCULATOR HAVING A PLURALITY OF PORTS IDENTIFIED SERIALLY IN THE DIRECTION OF PROPAGATION OF ENERGY IN SAID CIRCULATOR, MEANS FOR GENERATING A MICROWAVE SIGNAL AND DIRECTING SAID SIGNAL INTO A FIRST PORT, A TRANSMISSION LINE TERMINATED AT ONE END AND CONNECTED AT THE OTHER END TO A SECOND PORT, SAID TRANSMISSION LINE CONTAINING A CONTROLLABLE SHORTING MEANS LOCATED INTERMEDIATE SAID CONTROLLABLE SHORTING MEANS BEING SPACED A DISTANCE SUBSTANTIALLY EQUAL TO AN ODD MULTIPLE OF A QUARTER-WAVELENGTH AT THE OPERATING FREQUENCY OF SAID MICROWAVE CARRIER SIGNAL FROM SAID SHORTED END OF SAID TRANSMISSION LINE, MEANS FOR MODULATING SAID CONTROLLABLE SHORTING MEANS FROM A SUBSTANTIALLY NON-SHORTING CONDITION TO A SHORTING CONDITION, A UTILIZING CIRCUIT CONNECTED TO A THIRD PORT FOR RECEIVING SAID MODULATED CARRIER OUTPUT SIGNAL, AND MEANS CONNECTING SAID FERRITE CIRCULATOR FOR DISSIPATING UNUTILIZED RESIDUAL ENERGY IN SAID CIRCULATOR.
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US3316553A (en) * 1962-10-15 1967-04-25 Blass Antenna Electronics Corp Parallel feed antenna system with phase shift switching
US3414843A (en) * 1965-10-24 1968-12-03 Motorola Inc Four-part microwave ferrite circulator
US3437957A (en) * 1966-06-28 1969-04-08 Us Air Force Microwave phase shift modulator for use with tunnel diode switching circuits
US3460067A (en) * 1966-05-10 1969-08-05 Hughes Aircraft Co Precision wideband frequency modulator for injection locking a tuneable rf source
US3506930A (en) * 1967-07-18 1970-04-14 Collins Radio Co Broadband multilevel phase modulation system employing digitally controlled signal reflection means
US3706947A (en) * 1970-12-07 1972-12-19 Raytheon Co Variable phase equalizer
US3868602A (en) * 1973-09-20 1975-02-25 Varian Associates Controllable microwave power attenuator
US4004255A (en) * 1974-07-25 1977-01-18 Compagnie Industrielle Des Telecommunications Cit-Alcatel Microwave frequency phase modulator
US4142189A (en) * 1965-01-07 1979-02-27 The Magnavox Company Radar system
US4207525A (en) * 1966-12-12 1980-06-10 Westinghouse Electric Corp. Carrier control system for suppressed carrier modulators
US4710733A (en) * 1986-10-28 1987-12-01 Ford Aerospace & Communications Corporation r.f. Phase modulator
US4959654A (en) * 1987-04-20 1990-09-25 Honeywell Inc. Digitally generated two carrier phase coded signal source
US5847620A (en) * 1994-06-28 1998-12-08 Illinois Institute Of Technology Dielectric resonator phase shifting frequency discriminator
US6056496A (en) * 1996-06-21 2000-05-02 Cannon Equipment Company Cart loader and method of loading

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US2994828A (en) * 1959-07-13 1961-08-01 Bell Telephone Labor Inc Limiting in-phase, but not quadrature, sideband of a strong carrier by selective loading action of a diode modulator at the termination of a branching network

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US2994828A (en) * 1959-07-13 1961-08-01 Bell Telephone Labor Inc Limiting in-phase, but not quadrature, sideband of a strong carrier by selective loading action of a diode modulator at the termination of a branching network

Cited By (16)

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Publication number Priority date Publication date Assignee Title
US3316553A (en) * 1962-10-15 1967-04-25 Blass Antenna Electronics Corp Parallel feed antenna system with phase shift switching
US3289113A (en) * 1963-03-21 1966-11-29 Comp Generale Electricite Non-reciprocal attenuation equalization network using circulator having plural mismatched ports between input and output port
US3293550A (en) * 1963-07-23 1966-12-20 Rca Corp Transmit monitor
US4142189A (en) * 1965-01-07 1979-02-27 The Magnavox Company Radar system
US3414843A (en) * 1965-10-24 1968-12-03 Motorola Inc Four-part microwave ferrite circulator
US3460067A (en) * 1966-05-10 1969-08-05 Hughes Aircraft Co Precision wideband frequency modulator for injection locking a tuneable rf source
US3437957A (en) * 1966-06-28 1969-04-08 Us Air Force Microwave phase shift modulator for use with tunnel diode switching circuits
US4207525A (en) * 1966-12-12 1980-06-10 Westinghouse Electric Corp. Carrier control system for suppressed carrier modulators
US3506930A (en) * 1967-07-18 1970-04-14 Collins Radio Co Broadband multilevel phase modulation system employing digitally controlled signal reflection means
US3706947A (en) * 1970-12-07 1972-12-19 Raytheon Co Variable phase equalizer
US3868602A (en) * 1973-09-20 1975-02-25 Varian Associates Controllable microwave power attenuator
US4004255A (en) * 1974-07-25 1977-01-18 Compagnie Industrielle Des Telecommunications Cit-Alcatel Microwave frequency phase modulator
US4710733A (en) * 1986-10-28 1987-12-01 Ford Aerospace & Communications Corporation r.f. Phase modulator
US4959654A (en) * 1987-04-20 1990-09-25 Honeywell Inc. Digitally generated two carrier phase coded signal source
US5847620A (en) * 1994-06-28 1998-12-08 Illinois Institute Of Technology Dielectric resonator phase shifting frequency discriminator
US6056496A (en) * 1996-06-21 2000-05-02 Cannon Equipment Company Cart loader and method of loading

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